Part of the nutrients and organic matter in the organic fertilizer produced by fermentation of biogas residue using organic fertilizer production line technology are converted into humic acid substances, making it another type of organic fertilizer. In addition to rich elements such as nitrogen, phosphorus, and potassium, biogas fertilizer also contains trace elements such as calcium, iron, copper, zinc, manganese, and molybdenum, as well as bioactive substances that regulate the growth of animals and plants, and have killing effects on certain pests and diseases, such as amino acids, auxin, gibberellins, cellulose acids, monosaccharides, humic acids, and certain antibiotics. Biogas residue organic fertilizer has a high nutrient content, rich in organic matter and humic acid, and has the function of improving soil, making it suitable as a base fertilizer.

The selection of organic fertilizer production equipment required for the production of organic fertilizers using a biogas residue organic fertilizer production line. The processing of organic fertilizers for commodities requires two steps: early fermentation and processing, and deep processing and granulation. The supporting equipment for bio organic fertilizer includes fermentation turntables, organic fertilizer crushers, drum screening machines, horizontal mixers, rotary dryers, coolers, screening machines, coating machines, packaging machines, conveyors, and other equipment.

The characteristics of organic fertilizers produced by the organic fertilizer production line process are: ① Organic fertilizers containing sludge are rich in organic matter, humus, trace nutrients, various amino acids, enzymes, and beneficial microorganisms. The texture is loose, the moisture retention performance is good, and the acidity and alkalinity are moderate. After being decomposed into fertilizer by composting agents, it can play a good role in improving the soil. ② Organic fertilizer containing biogas residue contains elements such as nitrogen, phosphorus, and potassium, which can meet the needs of crop growth.

The problems in the production industry of organic fertilizer production line equipment can be summarized as follows:

(1) In the past forty years, with the increase of chemical fertilizer usage, although the total amount of organic fertilizer application has also been increasing, the proportion has relatively decreased, resulting in a continuous decline in soil organic matter, soil compaction, and salinization in some areas.

(2) The problem of fertilization machinery and habits is that the mechanization level of organic fertilizer fertilization is low, the labor intensity is high, and the application is inconvenient.

(3) The issue of industry standards for organic fertilizers is that the testing standards for organic matter in organic fertilizers are not scientific, lacking indicators for maturity and soluble organic matter, which affects the improvement of soil organic matter and is not conducive to the fertilizer utilization of livestock and poultry manure.

(4) Product quality and brand issues, the organic fertilizer industry has uneven product quality, fierce price competition, and weak industry brand awareness.

(5) The problem of slow progress in promoting the county system for livestock and poultry manure and biomass energy projects.